// 组合模式
const Folder = function(folderName) {
  this.folderName = folderName;
  this.files = [];
};

Folder.prototype.add = function(file) {
  this.files.push(file);
};

Folder.prototype.scan = function() {
  console.log(`开始扫描文件夹：${this.folderName}`);
  for (let i = 0; i < this.files.length; i++) {
    this.files[i].scan();
  }
};

const File = function(fileName) {
  this.fileName = fileName;
};

File.prototype.add = function() {
  throw new Error('文件下不能添加文件');
};

File.prototype.scan = function () {
  console.log(`开始扫描文件：${this.fileName}`);
}

// 测试
const folder = new Folder('文件夹');
const file1 = new File('文件1');
const file2 = new File('文件2');
folder.add(file1);
folder.add(file2);
folder.scan();
/*
开始扫描文件夹：文件夹
开始扫描文件：文件1
开始扫描文件：文件2
 */